The invention relates to a video signal recording apparatus and a reproducing apparatus and, more particularly, to a video signal recording apparatus and a reproducing apparatus using a small optical disk as an information recording medium and to an optical disk which is used for such apparatuses.
The recent improvement in the a recording density of an optical disk apparatus is remarkable. The recording density of data which can be used by the user per unit area has been improved at a rate of 40% a year. In a DVD (Digital Versatile Disc) system using an optical disk having a diameter of 12 cm, thus, a system such that data of 4.7 GB per side can be recorded as a DVD-ROM (Read Only Memory: overwriting is impossible), data of 3.9 GB can be likewise recorded as a DVD-R which can be overwritten only once, and further, data of 2.6 GB can be recorded as a DVD-RAM (Random Access Memory: rewritable any time) has been developed.
On the other hand, an image information compressing technique for reducing the amount of information in a motion image with small deterioration in picture quality has also progressed remarkably due to the development of an image processing technique. Particularly, since the MPEG2 image compressing algorithm by the MPEG (Motion Picture Experts Group) has been put into practical use, the recording and reproduction of a motion image of a low rate of 4 to 5 Mbps and an adequate picture quality can be performed.
Thus, the motion image of two or more hours can be recorded into a DVD-ROM of 4.7 GB and a DVD Video player using such a disk has been put on the market.
Since a lengthy motion image can be recorded on the optical disk as mentioned above, a motion image of time that is sufficient for practical use in an apparatus using an even smaller optical disk can be recorded.
The present invention has resulted from taking consideration of the foregoing situation and it is an object of the present invention to realize a small video image recording and reproducing apparatus using a small (for example, a diameter of 8 cm) optical disk. It is another object to enable an optical disk recorded by the above apparatus to be also reproduced by the foregoing DVD Video player. Still another object is to also improve its operability by the user.
In such a recording and reproducing apparatus of the video signal, it is better that both a write-once type (WO type) disk and a rewritable type disk can be used as an optical disk. This is because the WO type has different features such that although it is not rewritable, its recording density is high, a motion image of a long time can be recorded on the same disk, costs are generally lower than those of the rewritable type, and the like, while the rewritable type has features such that since it is freely rewritable, an image can be again recorded. It is, therefore, the first problem to enable a WO type optical disk and a rewritable type optical disk having different systems to be used by one apparatus.
The second problem is to enable the optical disk written by the present apparatus to be reproduced by a DVD Video player. The third problem is to enable an unfavorable portion to be unseen (erased) even in case of using a WO type optical disk.
To solve the first problem, a mark to distinguish the kinds of WO type optical disk and rewritable type optical disk is previously written on a cartridge or disk and means for detecting the mark is provided for a recording and reproducing apparatus, thereby enabling the kind of optical disk to be discriminated. Further, means for displaying a discrimination result to the recording and reproducing apparatus is provided, thereby preventing a mistake of the user. Means for properly controlling each optical disk is provided for the recording and reproducing apparatus, thereby performing the individual control in accordance with the discrimination result. Consequently, the optical disks of the two different systems can be used.
To solve the second problem, information which is written onto the optical disk has the same logical structure as that of an optical disk of a DVD video. For this purpose, means for recording both of a recording format called a UDF (Universal Disk Format) and the ISO9660 standard of the ISO (International Standardization Organization) as file management information is provided. Further, when there is an unrecording area on the optical disk, the DVD Video player is likely to cause an erroneous operation at a boundary between the recording area and the unrecording area. Therefore, means for recording a special signal to prevent the occurrence of the erroneous operation in the boundary portion is provided. That is, by the special signal recorded in the boundary portion, a track searching operation when a pickup jumps to a target track is normally executed without an erroneous operation. When the special signal is recorded, however, since an area where the inherent video signal can be recorded decreases, the number of times of writing the special signal is reduced. For this purpose, as for the timing to record the special signal, means for automatically recording the special signal at a timing when the optical disk is ejected, a timing when a residual amount of a battery decreases, or the like is provided. Even if the optical disk is taken out in the halfway, it is prevented that the special signal can be recorded. With this construction, after the optical disk was taken out in the halfway, even if the user retries to load the optical disk into the same apparatus and to record, unless the previous file management information remains, final file management information including the previous file management information cannot be made. Therefore, means for recording data to make the final file management information (hereinafter, this data is called intermediate information) onto the optical disk is provided. By using the optical disk on which the intermediate information has been recorded, the final file management information can be formed from the intermediate information recorded on the optical disk. It is not always necessary to record the intermediate information onto the optical disk. It is also possible to provide storing means into the apparatus and to store the intermediate information.
As for the timing for recording the intermediate information, it can be recorded when the optical disk is ejected from the apparatus or when it is believed that the apparatus cannot normally record information onto the optical disk.
By the above construction, the final file management information can be made and the file management information which can be reproduced by the DVD Video player can be recorded.
The process to make the final file management information from the intermediate information recorded on the optical disk can be automatically executed by the apparatus or can be also executed by a process activating instruction of the user.
That is, by recording the intermediate information, the final file management information which can be reproduced by the DVD Video player can be made. In order to allow the track searching operation to be executed without an erroneous operation upon reproduction of the DVD player, the special signal has been recorded. Further, by reducing the number of times of recording the special signal, the recordable area on the optical disk is increased.
To solve the third problem, means for changing in a manner such that file management information on the WO type optical disk cannot be accessed to the instructed file by an erasing instruction of the user is provided. With this construction, although the reproduction is impossible in the ordinary file management system, means for overwriting meaningless data onto the data and destroying the data is also provided for safety, thereby also enabling the data to be perfectly erased.